They haven't changed a lot but just like everything else, the quality of workmanship isn't the same on the new ones as it used to be. They have only made a couple of design changes over the years with the lid hinges and the chimney, I do believe the metal is a little thinner, especially on the inserts compared to early ones but it goes to show that the original idea must have been a pretty good one to last most of 80 years.